Crowdin Apps SDK

The Crowdin Apps SDK is a Node.js framework for building self-hosted apps. You describe the app in a configuration object, and the SDK builds the Express application around it, with the endpoints Crowdin calls already in place.

Because they run on your own server, self-hosted apps support every module type, including file processing, AI providers, custom machine translation engines, and webhooks.

What the SDK Handles

• Authentication: OAuth 2.0 with the crowdin_app grant type, JWT validation, and context extraction.
• Modules: Registration and the endpoints each module type expects.
• Database: SQLite by default, with PostgreSQL and Cloudflare D1 as options.
• File storage: Temporary files for file processing modules.

Building a Self-Hosted App

Install the package:

npm install @crowdin/app-project-module

Apps built with the SDK deploy to Vercel, AWS Lambda, and Cloudflare Workers.

Crowdin Apps SDKSetup, configuration, modules, database, deployment, and security guides.

When to Build a Serverless App Instead

If your app is all interface (a dashboard, an editor panel, a menu extension), you can build it as a serverless app: Crowdin hosts and runs it, and there is no server to deploy or maintain.

Read more about the Serverless Apps SDK.